/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache Lucene" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache Lucene", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

using System;
using System.Collections.Generic;

namespace DotnetPark.NLucene.Documents
{
	/// <summary>
	/// A simple implementation of IEnumerable to iterate through document fields.
	/// </summary>
	internal class DocumentFields : IEnumerable<Field>
	{
		Document d;

		internal DocumentFields(Document d)
		{
			this.d = d;
		}

		// IEnumerable Interface Implementation:
		//   Declaration of the GetEnumerator() method 
		//   required by IEnumerable
		public IEnumerator<Field> GetEnumerator()
		{
			return new DocumentFieldEnumerator(d);
		}

		System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
		{
			throw new NotImplementedException("Use Generic Implementation!");
		}

		private class DocumentFieldEnumerator : IEnumerator<Field>
		{
			DocumentFieldList fields;
			Document d;

			internal DocumentFieldEnumerator(Document d)
			{
				this.d = d;
				Reset();
			}

			// Declare the Reset method required by IEnumerator:
			public void Reset()
			{
				fields = d.fieldList;
			}

			// Declare the Current property required by IEnumerator:
			public Field Current
			{
				get
				{
					Field result = fields.Field;
					fields = fields.Next;
					return result;
				}
			}

			// Declare the MoveNext method required by IEnumerator:
			public bool MoveNext()
			{
				return fields == null ? false : true;
			}

			public void Dispose()
			{ ;}

			object System.Collections.IEnumerator.Current
			{
				get { throw new NotImplementedException("Use generic implementation!"); }
			}
		}
	}
}